Apparatus for indicating defective eyesight.



No. 837,368. PATENTED DEC. 4, 1906. J. J. WOOD.

APPARATUS FOR INDIOATING DEFECTIVE EYBSIGHT.

APILIGATION FILED APR.27.1905,

sums-sum 1 No. 837,368. PATENTED DEC. 4, 1906.

J. J. WOOD.

APPARATUS FOR INDIGATING DEFECTIVE EYESIGHT. APPLICATION FILED APR. 27, 1905.

2 SHEETS-SHEET 2 front of and away PATENT JOHN JAMES WOOD, OF LIVERPOQL, ENGLAND.

APPARATUS FDR lNDlCATlhlG DEFEGTlVE EYESlC-Ifi'l'f'.

Specification of Letters Patent.

Patented Dec. 4:, 1906.

Application filed April 27, 1 905. Serial No. 257,705-

be described with the aid of the accompanying drawings, in

Figure 1 is a side elevation, partly in section, showing one form of apparatus for illustrating defective eyesight and its correction by spectacles. Fig. 2 is a front view of the art of the apparatus shown on the left-hand side of Fig. l and Fig. 3 is a front view of the part of the apparatus shown on the right-hand side of Fig. 1.

mg a modification for illustratin mechanically the defects of short sight and long sight.

Referring to the. drawings, the apparatus comprises a model of a part of the skull a of a erson endhaving in it an aperture showing the lens and retina of the eye.

6 is an artificial light contained within a box if, havin a translucent dial 9 between the amp and the skull a, the dial having upon it suitable letters or signs, which are to be thrown onto the retina portion of the eye in the skull a. Between the skull a and the dial g spectacles t are introduced, they being intermittently and mechanically moved in from the eye-lens.

With re ard to the skull a in the side there is a cavity in it, which is open to the outside of the head. The back portion of this cavity is in the form of a concave curve 0, while in front of the cavity is the eye-lens 67., so laced in frontof the curved surface 0 that t e objects reaching the lens are reflected onto the sugface c and can be seen thereon from out- S]. e.

lhe spectacles 'i have an ordinary lens 'i and are adapted to be raised from the position as shown in full lines in Figs. 1 and 2 to a oint away from the skull alternately. This movement is effected by an arm hinged at 7r, about which it is adapted to be vibrated from the horizontal positlon shown to a suitable angle upward and back again by any suitable Fig. i is a side elevation showkind of known mechanism. in the case shown the letters H O H are provided on the glass g,which are illuminated from behind by the electric lamp e, and thereby intensified. tors is received by the lens d and is transmitted by it onto the retina-surface c, which shows them reflected on it.

To illustrate defective eyesight by the apparatus, the lens relation to the retina c that images received by the lens are rendered indistinct or blurred on the retina, and to illustrate the effect of utilizing proper spectacles the lens of the The image of these letd is such and so placed in spectacles 'b, which must be of the required character, is caused to moved in front of the lens (1, whereu on the image on the retina c, which was indistinct and confused, is at once rendered sharp and clear, and thereupon the a aratus shows and illustrates, t c defects of vision and their correction by spectacles. Around the illuminated glass g, which, say, is a frosted glass with the figures H O H on it, there is a large frame it, preferably with a darkened surface, which assists in intensifying the image and obviating interference of the images of other surrounding objects in the lens. Thus these two states of the picture or reflection, the one blurred andthe other sharp and defined, illustrates what happens to people with defective eyesight when they use ro er glasses and when they do not. The srul or body a and the other parts of the apparatus are all suitably mounted on a base 25.

Referring now to Fig. 4, this apparatus may be used with or without the spectacles or less lens to indicate and illustrate the dilfe ent effects of distance of an object looked at to people with long and short sight. In this case the casing f, containing the lamp e and front h with a glass, as g, (shown in Figs. 1'-to 3)'in its face is moved nearer to and farther from the skull a. To effect'this movement, these parts are mounted on a slide Z, which works in a guide m, fixed on the SlZ2l-11(liLI(l -)L,'lih6 slide]. being operated by a connecting-rod 0 and crank 37, mounted on an axle g on the frame 1" and adapted to be suitably revolved by any known suitable means. The skull. is similarly, as in the case shown in Figs. 1 to 3, provided with a chamber 1), a lens d in the front, and a concave retina-surface 0. Assumin the lens (Z were such and its position in relation to the retina 0 were as stated,

such that when the object were farthest away from it it Wouldgive a blurred picture or image on the retina, c, which would illustrate the condition of e short-sighted person, and

to him, and similar or analogous effects and purposes. What IS cleimed 1s- 1. Apparatus for mechanically indicating assuming the farther distance referredto was defective eyesight, and the correction ,of

the normal distance, then as the objeet was moved nearer the lens d the image or picture on the retina would become clearer and when at its nearest point its image would. be sharp and defined, endthus the apparatus would illustrate the defective eyesight or ision in the case of s short-sighted person. Conversely, if the lens d and its position in relation to the retina 0 were such that when the object in the plate h were nearest the lens d (which may be assumed to be the normal distance in this case) the image on the retina c pushed farther away by the crank p this image or picture becomes clearer or more sharp and defined then the apparatus would illustrate the effects of objects as seen nearer to and. farther from the eyelens by a person of long sight. In it case such as is shown in with it spectacles, as set forth with reference to Figs. 1 to 3, by means of which there can be used for trating the effect to people using such spectacles and the effect of at diflerent distances. p

' It will be therefore seen that the apparatus can be used for several purposes connected with the illustrating of defects of vision and their correct-ion by spectacles or losses. Examples of such uses are that it wi 1 show how long sight can be corrected, how short sig ht can he corrected, the defects of wrong spectacles, the reason why an old-sighted person sees better by holding print away frpin him, the reason Why a short-sighted person sees better by holding print quite near is blurred and that when the object is.

4 there may be also used in connection and shown suitable spectacle lenses long and short sighted people and illus=- looking at objects:

a body 0: having e chem" side, and having a lens (5 in the front, and a receiving-surface c at the back; an object 9 in front of the lens (3, the image of which is adapted to be received by the lens (2," a lens i, and means for moving the said lens 2' in front of and awe from the lens (1 between such lens end the object 9. 2..Apparaius for mechanically indicating defective eyesight, end the correction of same, consisting of a body a havingjr chem- UP! I) open from the side, and having a lens d in the front, and :1 receiving-surface c at the buck, an object 9 in front of the lens d, the image of which is adapted to be received by the lens 0!; a window 9, having upon it the objects to be received by the lens; and en artificial light e behind the window 9 for intensifying the object; substantially as set forth.

3. Apparatus for mechanically indicating same, consisting of her b open from the defective eyesight, and the correction of same, consisting of a body at having a chember I) open from the side, and having a lens d in the front, and a receiving-surface c at the back; an object gin front of the lens (1, side ted to be received by the lens (2', and movable up to and away from the lens (I; and means connected with said 0 )ject for so moving it nearer to and farther rom the lens; substantially as set forth. I

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

JOHN JAMES WOOD. Witnesses:

S. GOODALL, W. HARRISON. 

